JP3384401B2 - Variable capacity swash plate compressor - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable displacement swash plate type compressor used for vehicle air conditioning. 2. Description of the Related Art A conventional variable displacement type swash plate type compressor (hereinafter, referred to as a swash plate type compressor).
It is simply called a compressor. ) Is disclosed in JP-A-60-17578.
No. 3 is known. In this compressor, as shown in FIG. 5, a cylinder block 2 having a plurality of bores 21 is disposed at a central portion, and a front end of the cylinder block 2 forms a closed crank chamber 31 and is closed by a front housing 3. The rear end is closed by a rear housing 4 via a valve plate 41. Rear housing 4
Is provided with a suction chamber 42 and a discharge chamber 44 that communicate with the bore 21. A drive shaft 5 is inserted and supported in a shaft hole of the cylinder block 2, and a swash plate 6 rotatably housed in a crank chamber 31 is mounted on the drive shaft 5 so as to swing. Have been. The piston 1 fitted into the bore 21 is moored to the swash plate 6 via a shoe 7. The piston 1 has a main body that is in sliding contact with the inner peripheral surface of the bore 21 and a shoe connecting part that is provided integrally with the main body and connects the shoes. The cylinder block 2 is provided with a communication hole 23 that connects the crank chamber 31 and the suction chamber 42, and the communication hole 23 opens and closes in accordance with a pressure difference from the suction pressure. Bellows 8 is provided. In this compressor, when the swash plate 6 rotates with the driving of the drive shaft 5, each piston 1 reciprocates in the bore 21, whereby the refrigerant gas sucked into the bore 21 from the suction chamber 42. Is discharged to the discharge chamber 44 after being compressed. At this time, the compression capacity of the refrigerant gas discharged to the discharge chamber 44 is:
The control is performed by adjusting the pressure in the crank chamber 31 by opening and closing the communication hole 23 by the differential pressure between the suction pressure and the set pressure of the bellows 8. That is, when the suction pressure is higher than the set pressure of the bellows 8, the communication hole 23 is opened, the pressure in the crank chamber 31 is reduced, and the stroke of the piston 1 and the inclination angle of the swash plate 6 are increased. Thus, the compression capacity is increased. Conversely, when the suction pressure is lower than the set pressure of the bellows 8, the communication hole 23 is closed and the pressure in the crank chamber 31 is increased, and the stroke of the piston 1 and the inclination angle of the swash plate 6 are reduced to compress. The capacity is smaller. [0006] A part of the refrigerant gas sucked into the bore 21 leaks into the crank chamber 31 and becomes swash plate 6 or shoe 7.
It is used as lubricating oil for sliding parts. By the way, the piston 1 of the above-mentioned compressor is provided with a concave portion having a large opening on the shoe connecting portion side in the main body portion, thereby reducing the weight. On the other hand, the compressor has a structure in which the reciprocating motion of the piston 1 in the bore 21 is caused by the rotational motion of the swash plate 6, and a compression reaction force and an inertial force act when the piston 1 reciprocates. The piston 1 is required to have sufficient strength. Therefore, in the case of the piston 1, it is necessary to secure a sufficient strength by increasing the thickness of the main body portion on the shoe connecting portion side or the like, and it is not possible to achieve a sufficient weight reduction. SUMMARY OF THE INVENTION It is an object of the present invention to provide a variable displacement swash plate type compressor capable of ensuring sufficient strength of a piston and reducing the weight. A variable displacement type swash plate type compressor according to the present invention comprises: a cylinder block having a plurality of bores;
A front housing for closing a front end of the cylinder block by forming a closed crank chamber; a rear housing having a suction chamber and a discharge chamber for closing a rear end of the cylinder block; and a shaft hole of the cylinder block. A swash plate rotatably mounted on the drive shaft and rotatably accommodated in the crank chamber; and a moored to the swash plate via a shoe to reciprocate in the bore. A variable displacement swash plate type compression, wherein a compression capacity is controlled by changing a stroke of the piston and an inclination angle of the swash plate according to a differential pressure between a pressure in the crank chamber and a suction pressure. in machine, the piston, the inner peripheral surface in sliding contact body portion of said bore, provided integrally with the body portion, and a shoe connecting portion for connecting said shoe to the body portion, said Occlusion vital to-menu connecting portion side in the radial direction
A closed hollow portion is formed by a side wall for anchoring the shoe, and a through hole communicating the hollow portion with the outside is provided on the shoe connecting portion side of the main body portion. According to this means, it is possible to sufficiently secure the strength required on the shoe connecting portion side of the main body, and it is possible to reduce the weight by reducing the thickness of the main body. Such a piston can be formed by integrally joining at least two members by welding.
By employing such a manufacturing method, the hollow portion can be easily processed by, for example, cutting, and the thickness of the main body can be easily reduced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
A description will be given based on FIG. In addition, since the compressor of the embodiment is the same as the conventional compressor shown in FIG. 5 in the basic configuration, common members and the like are denoted by reference numerals,
Except for the piston which characterizes the present invention, detailed description of common members and the like is omitted. As shown in FIGS. 1 to 3, the piston 1 used in the compressor according to the embodiment includes a cylindrical main body 12 slidably in contact with the inner peripheral surface of the bore 21,
2 and a shoe connecting portion 18 for connecting the shoes 7, and a closed hollow portion 11 is formed in the main body portion 12. The main body 12 of the piston 1 has a side wall 19 that closes the hollow portion 11 in the radial direction on the shoe connecting portion 18 side. The shoe connecting portion 18 includes an arm portion 16 extending in the axial direction from the main body portion 12 and a holding portion 17 formed to face the side wall 19 from the arm portion 16. An annular oil groove 13 is formed on the outer peripheral surface of the main body 12. The oil groove 13 is provided at a limit position where the oil groove 13 is not exposed to the crank chamber 31 when the piston 1 is located at the bottom dead center in the bore 21 as shown in FIG. The oil groove 13 is provided with three first through holes 14 opened at the bottom of the groove and communicating the hollow portion 11 with the outside at equal angular intervals. As shown in FIG. 3, on the shoe connecting portion 18 side of the main body portion 12, three second opening portions that open to the peripheral portion of the end surface and communicate the hollow portion 11 with the outside are provided.
The through holes 15 are provided at equal angular intervals. Further, a holding portion 17 having an inner surface formed symmetrically with an end surface of the main body portion 12 is provided on the shoe connecting portion 18 side of the main body portion 12 via an arm portion 16 extending in the axial direction. The piston 1 is formed by integrally joining two members by welding. By adopting such a manufacturing method, the hollow portion 11 can be easily processed by, for example, cutting, and the thickness of the main body 12 can be easily reduced. The piston 1 configured as described above has a shoe 7 slidably disposed on both sides of the swash plate 6 with the peripheral edge of the swash plate 6 inserted between the main body 12 and the holding portion 17. And is fitted and disposed in each bore 21 of the cylinder block 2. In the compressor of the embodiment equipped with the piston 1 configured as described above, when the swash plate 6 rotates with the driving of the drive shaft 5, each piston 1 reciprocates in the bore 21. As a result, the refrigerant gas sucked into the bore 21 from the suction chamber 42 is compressed and discharged to the discharge chamber 44. During this time, the piston 1 can secure sufficient strength required on the shoe connecting portion 18 side of the main body 12 and can be reduced in weight by reducing the thickness of the main body 12. It is. In addition, when the pressure in the bore 21 repeats the high pressure state and the negative pressure state with such an operation, a breathing action occurs between the bore 21 and the hollow portion 11 through the first through hole 14. In addition, in response to this respiratory action, a respiratory action occurs between the hollow portion 11 and the crank chamber 31 via the second through hole 15, and the bore 21
The breathing action between the and the hollow portion 11 is performed smoothly. As a result, the pressure difference between the bore 21 and the hollow portion 11 is reduced, so that the thickness of the main body 12 can be reduced while ensuring strength, and the weight of the piston 1 can be reduced. A lubricating oil contained in the refrigerant gas adheres to the inner peripheral surface of the bore 21, and the lubricating oil is scraped off by the oil groove 13 when the piston 1 reciprocates. For this reason, a high concentration of refrigerant gas flows out into the hollow portion 11 and further into the crank chamber 31 with the above-mentioned respiratory action, and lubrication of sliding parts such as the swash plate 6 and the shoe 7 operated in the crank chamber 31 is performed. It plays a suitable role as an oil. In this case, the second through hole 1 in the embodiment
5 is provided so as to face the shoe 7, and FIG.
As shown in FIG. 3, three pistons 1 of the embodiment are provided at equal angular intervals in consideration of the case where the pistons 1 are disposed in the cylinder block 2 of six cylinders, so that the swash plate 6 having the most slidable sliding conditions is provided. Lubricating oil can be uniformly supplied to the shoe 7.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view of a piston according to an embodiment. FIG. 2 is a sectional view of a piston according to the embodiment. FIG. 3 shows a piston according to the embodiment,
FIG. 3 is a sectional view taken along line III. FIG. 4 is an explanatory view showing an arrangement of a second through hole of a piston provided in a cylinder block in the embodiment. FIG. 5 is a sectional view of a conventional variable displacement swash plate type compressor. [Description of Signs] 21 ... Bore 2 ... Cylinder block 31 ... Crank chamber 3 ... Front housing 42 ... Suction chamber 44 ... Discharge chamber 4 ... Rear housing 5 ... Drive shaft 6 ... Swash plate 7 ... Shoe 1 ... Piston 12 ... Main body 18 shoe connecting part 11 hollow part 14 first through hole 15 second through hole 19 side wall

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-10-281065 (JP, A) JP-A-11-107912 (JP, A) JP-A-6-307333 (JP, A) 109481 (JP, U) Japanese Utility Model Showa 55-60470 (JP, U) Patent 2917927 (JP, B2) JP-B 64-1668 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) ) F04B 27/08 F04B 39/00 107

Claims (1)

(57) [Claim 1] A cylinder block having a plurality of bores,
A front housing for closing a front end of the cylinder block by forming a closed crank chamber; a rear housing having a suction chamber and a discharge chamber for closing a rear end of the cylinder block; and a shaft hole of the cylinder block. A swash plate rotatably mounted on the drive shaft and rotatably accommodated in the crank chamber; and a moored to the swash plate via a shoe to reciprocate in the bore. A variable displacement swash plate type compression, wherein a compression capacity is controlled by changing a stroke of the piston and an inclination angle of the swash plate according to a differential pressure between a pressure in the crank chamber and a suction pressure. in machine, the piston, the inner peripheral surface in sliding contact body portion of said bore, provided integrally with the body portion, and a shoe connecting portion for connecting said shoe to the body portion, said Shoe connection
Side wall that closes radially on the part side and anchors the shoe.
A swash plate type compressor having a variable capacity, wherein a closed hollow portion is formed, and a through hole communicating the hollow portion and the outside is provided on the shoe connecting portion side of the main body portion. .